Sound-reproducing device



Oct. 15, 1929. NEMNICH 1,731,905

SOUND REPRODUCING DEVICE Filed May 17, 1926 llllllllh' INVENTOR gym A Patented Oct. 15, 1929 UNITED STATES PATENT ()FFKZE GUS NEMNICH, OF NEW YORK, N. Y., ASSIGNOR OF ONE-FIFTH TO FRED FREDERICK, OF

' NEW YORK, N. Y.

SOUND-BEPRODUCING DEVICE Application filed May 17,

. This invention relates to means for reproducing sounds, for example, by changing sound controlled electrical variations into mechanical vibrations or sound waves, or vice versa.

The object of the invention is to provide an electromagnetic sound reproducing device in which the armature is so guided and supported that it vibrates in one plane in the direction of the magnetic lines of force, that is, all points on the armature will move in lines parallel to the direction of these lines of force.

A further object is to construct a simple and efficient mechanism to guide and support the armature in its straight line vibrations.

Another object is to construct said guiding and supporting means to wholly support and actuate a diaphragm in any position Without retarding or straining the vibratory parts.

Other objects and advantages will hereinafter appear.

Referring to the drawings:

Fig. 1 is a view in elevation partially in section showing the preferred form of my invention.

Fig. 2 is a View in section taken on line 22 of Fig. 1.

Fig. 3 is a sectional view taken on line 33 of Fig. l.

Fig. 4 is a fragmentary perspective view of the pole pieces of the magnet.

Fig. 5 is a sectional view of another form of my invention.

Fig. 6 is a sectional View taken on line 66 of Fig. 5.

Fig. 7 is a perspective view of the form of magnet and pole pieces used in the device shown in Fig. 5.

Fig. 8 is a sectional view. of a loud speaker showing the application of my preferred form therein.

Referring to Figs. 1, 2 and 3 numeral 2 denotes a permanent magnet of the horse-shoe type rigidly carried by a support plate 4, which may be secured in any Well known manher to the body of a loud speaker as shown in Fig. 8.

The ends of the permanent magnet securely carry lugs 4 and 6 extending towards each 1926. Serial No. 109,655.

other, lug 4 carrying spaced pole pieces 4 and 4", and lug 6 carrying spaced pole pieces 6 and 6 The pole pieces 4 and 6 overlap to form an air gap 8 and pieces 4 and 6 overlap to form an air gap 10, which is spaced away from the air gap 8.

In the space 12 formed by the spaced pole pieces, coils 14 and 16 are mounted having openings 14 and 16*, respectively, in alignment with the air gaps 8 and 10 as illustrated in Fig. 3. The coil 14 is positioned adjacent the pieces 4 and 6 and coil 16 is positioned against the pole pieces 4 and 6, so that a space is provided between them. The coils are, of course, wound in series and are held in the positions indicated by reason of the arcuate surfaces 4 and 6 formed in the lugs 4 and 6, respectively, between their extending pole pieces. These lugs may be formed, each of one piece or of laminated sections.

' The surfaces of the pole pieces which form the air gapsare in parallel planes and an armature 18, preferably a stiff bar of iron having parallel surfaces, is positioned centrally in the gaps with its surfaces parallel to the surfaces of the pole pieces. The armature of course, extends through the holes 14 and 16 of the coils 14 and 16. The armature is rigidly carried by a, stiff metal stylus or rod 20 which extends through the centre of the armature 18 at right angles thereto and is positioned in the space between the coils and is movably carr ed by space bars 22, as particularly illustrated in the Fig. 3.

These bars 22 are of metal and are arranged in parallel planes with respect to the length of the armature and on opposite sides thereof and are turned at 90 degrees in relation to the length of the same. The bars 22 have ends 22 and 22 which are secured to posts 24 extending in parallel to the stylus 20. These posts may be secured to any part of the support 4 and theends 22 and 22 are securely clamped upon the same by reason of nuts 26 threaded upon the posts. The bars 22 have holes centrally iocated to reecive the stylus 20 which is threaded to receive nuts 28 clamping the bars on both sides. The bars as shown in Figs. 1, 2, and 3 are rendered inflexible for some distances on both sides of the stylusby having their sides bent as indicated by 30. Each bar has flexible portions 22 and 22", Figs. 1 and 2 located near its ends where the reenforcing sides 30 terminate. These flexible portions are formed by flat semi-circular bends which are of practically equal flexibility and are equi-distant from the stylus 20.

The flexible portions 22 and 22 are of course of sufficient tension and equality to keep the armature 18 centrally positioned in the air gaps'- 8 and 10 as indicated in Figs. 1 and 3.

WVhen the coils 14 and 16 are e'nergizedby a variable current, variable magnetic lines of force are produced at the pole pieces 4, 6 4 'and 6", thus causing the armature 18 to vibrate to and from the surfaces of the pole pieces. The pole pieces 4 and 6 simultaneously attracting the armature while the pieces 4" and 6 simultaneously repel the armature or vice versa, according to the variations of the magnetic field. The magnetic lines of force produced in the gaps act upon the surfaces of the, armature at right angles thereto. and it will be noted that the stylus supporting the armature is arranged parallel to the magnetic lines of force.

The vibration of the armature to and from the poles are permitted by the flexible portions or bends 22 and 22 of the bars 22. The re-enforced portions of the bars, the stylus 20 and the armature 18 move as one rigid piece upon the ends 22 and 22 by reason of these flexible portions.

The bars 22 are so constructed and mounted in relation to the armature 18, and the flexible portions are so formed upon the 'bars that the stylus 20 is guided to vibrate strict- 1y longitudinally in the same direction as the magnetic lines of force, when the armature is actuated by the magnetic fields. Therefore, the surfaces of the armature when vibrated, will at all times be parallel to the surfaces of the magnetic poles, and by reason of its mounting will be prevented from making any other movement than its vibratory one.

The flexible portions 22 and 22 of the bars 22 are of suflicient tension to return the armature to its central position after it has been actuated and to rapidly change the vibrations of the armature from high frequencies to low frequencies or vice versa in accordance with the frequency variation of the magnetic fields.

As illustrated in Figs. land 3, the stylus 20 actuates a diaphragm 32. This diaphragm may be of any well known type, such as a cone, which may be entirely supported and actuated by the stylus 20 as disclosed in Fig. 8. The stylus 20 by reason of its supporting bars 22 may conveniently carry and actuate the large, heavy cone diaphargm in any position, without impairing or retarding perdiaphragm, clear tones of low and'high frequency.

If desired the bars 22 need not be angularly offset in relation to the armature. These bars may also beangularly offset in relation I to one another. If necessary only one bar 22 can be used to support the armature and the stylus.

In order to prevent-the conflict of magnetic forces of opposite polarity at the center of the. armature near its stylus the coils 14 and'16 have their holes 14 and 16 beveled as indicated by numerals 14" and 16 in Fig. 3. This beveling reduces the proximity of the coils of wire near the center of the armature and thus concentrates the magnetic field near the end of the armature.

The position of the armature 18 in relation to the air gaps 8 and 10 may-be readily adjusted in all planes by reason of its mounting. The position of the armature to and from the surfaces of the pole pieces is readily stylus 20. This mounting also permits the armature to be'adjusted angularly in relavibratory plane.

The tension of the flexible portions 22 and 22 may be readily increased or decreased V changed by reason of the nuts 28 upon the as desired, by forcing the ends 22 and 22 no toward or from each other along the posts 24. This will render the armature adjustable in relation to themagnetic forces.

As the vibratory movements are very slight the flexible portions 22 and 22 will only be slightly affected and as these portions are of equal flexibility the armature will be guided in a direction parallel to the lines of force. As the minute vibrations must transmit a certain frequency it will be understood that it is advantageous to so guide the vibratory parts in the direction of the lines of force that there is a faithful reproduction. of clear tones at the diaphragm.

my invention. This device comprises a mag- Fig. 5,6 and 7 illustrate another forni of net 34 having a straight end 36 and an end i 38 bent at right angles to the end 36. The end 36 rigidly carries a lug 40 which is substantially a horse-shoe in shape and carries spaced pole pieces 42 and 44 facing each other. The bent end 38 carries a lug 46 extending parallel to the end 36, the said lug 46 carrying pole pieces 48 and 50 facing in opposite directions to form with the pole pieces 42 and 44 air gaps 52 and 54. The lug 46 is so formed in a portion of its length to avoid the lug 40 in order to prevent any leak in magnetic forces.

The faces of the poles are parallel to each other and positioned in the air gaps formed by said faces is an armature 56. The armature is designed in the form of a horse-shoe having a middle portion 58, integral end portions 62 and 60 extending at right angles to the middle portion 58. These end portions extend into the gaps 52 and 54, and the surfaces of these portions are parallel to each other and to the surfaces of the poles which form the air gap.

For the purpose of creating variable magnetic lines of force in the air gaps 52 and 54 in directions perpendicular to the surfaces of the poles, coils 64 and 65 are provided. These coils are wound in series and the coil 64 is secured adjacent the pole pieces 42 and 48 with a hole 64 therein aligned with the air gap 52, and the coil 66 is secured against the pole pieces 44 and 50 with a hole 66 therein aligned with the air gap 54.

The armature 56 is carried by a stylus 68 which extends through the portion 58 of the same and is held against movement upon this stylus by means of nuts 7 0 which are. threaded on the stylus. The armature 56 and its stylus 68 are carried by bars 22 in such a manner that the stylus extends in a direction parallel to the magnetic lines of force.

The bars 22 are of the same construction as the bars illustrated in my preferred device and serve the same purpose in the same manner. The flexible portions thereof yieldingly hold the armature in the center. of the air gaps and also permit the movement of the armature in accordance with'the variations of the magnetic field when the coils are energized. The bars and their bends also serve to strictly guide the stylus in a strictly longitudinal direction so that the cone carried by the stylus is actuated without any side thrusts or distortions,

The holes 64 and 66 of the coils 64 and 66 are also beveled as indicated by the numerals 64 and 66 in the Fig. 5, so that the magnetic forces are directed to the portions of the armature which lies in the air gaps.

The vibratory parts, that is, the armature 56, the stylus 68, and the stiff portions of the bars 22, move as one rigid piece upon the ends 22 and 22*, by reason of the flexible portions 22 and 22 of the bars 22. This vibratory unit may be adjusted in' any plane in the same manner as the vibratory unit of my preferred device.

Fig. 8 illustrates my preferred device mounted in a loud speaker, in which the diaphragm is wholly supported and actuated by a horizontally positioned stylus. The free edge of the cone diaphragm is positioned in an angular space 72 formed in the loud speaker frame, which frame carries a horn 72 to direct the sound produced by the diaphragm. This figure illustrates the bars 22 supporting the stylus intermediate the armature and the diaphragm.

Various changes may be made in the form of my invention without departing from the spirit and scope thereof as defined in the claims.

What I claim is:

1. In an electro-magnetic sound reproducer the combination, a support, an armature, a means for creating variable magnetic lines of force to actuate the armature, a stylus attached to said armature extending in a direction parallel to the lines of force, means upon the support directly connected to the stylus to wholly guide and support the stylus so that it vibrates in the direction of the magnetic lines of force, a diaphragm actuated by the stylus.

2. In an electro-magnetic sound reproducer the combination, a support, an armature,xa means for creating variable magnetic lines of force to actuate the armature, a stylus attached to said armature extending in a direction parallel to the lines of force. means upon the support to wholly guide and support the stylus so that it vibrates in the'direction of the magnetic lines of force, a, diaphragm wholly supported and actuated by the stylus.

3. In an electro-magnetic sound reproducer the combination, a support, an armature, a diaphragm, a means for creating variable magnetic lines of force to actuate the armature, spaced bars arranged in parallel carried by the support, a stylus connecting the armature with the bars, a diaphragm connected with the stylus, means upon the bars to guide the second said means in the direction of the magnetic lines of force when the armature is actuated.

4. In an electro-magnetic sound reproducer the combination, a support, an armature, a means for creating variable magnetic lines of force to actuate the armature, abar secured to the support, a stylus upon the bar to wholly support the armature, a diaphragm connected to the stylus, a means upon the bar to wholly guide and support the stylus so that the same will move in the direction of the lines of force when the armature is actuated.

5. In an electro-magnetic sound reproducer the combination, a support, an armature, a means for creating variable magnetic lines of force to actuate the armature, spaced bars one above the other and arranged in parallel and transverse to the lines of force and secured to the support, means upon the bars to wholly I carry the armature, a diaphragm, means connecting the bars with the diaphragm, means upon the bars to guide both said means in the direction of the lines of force when the armature is actuated.

' 6. In an electro-magnetic sound reproducer the combination, a support, a means for creating variable magnetic lines of force, an armature arranged transversely to said lines and adapted to be actuated thereby, a stylus connected centrally to the armature and extending in the direction of the lines of force, spaced bars arranged in parallel to each other and the armature having their ends secured to the support and having their center portions connected to the stylus to wholly support the same, of flexible portions in said bars to permit the stylus to move strictly longitudinally in the direction of the lines of force when the armature is actuated, a diaphragm actuated by the stylus.

7 In an electro-magnetic sound reproducer the combination, a support, a means for creating variable magnetic lines of force, an armature arranged transversely to said lines and adapted to be actuated thereby, a stylus connected centrally to the armature and extend ipgdn the direction of the lines of force,

spaced barsarranged in parallel to each other and the armature having their ends secured to the support and having their center portions connected to the stylus to Wholly support the same, flexible portions in said bars udinallyin the direction of the'lines of force permit/the stylus to move strictly longi when the armature is actuated, a diaphragm wholly suppored and actuated by the stylus.

8. In an electro-magnetic sound reproducer the combination, a support, a means for creatirg variable magnetic lines of force, an arma ture having its length arranged transversely to the lines of force and adapted to be actuated thereby, a stylus connected to the arma: ture and extending in the direction of the lines of force, spaced bars arranged in parallel to each other and the armature "and crosswise to the length of the same and'having their ends secured to the support and having diaphragm, a means upon the armature to fwholly support and actuate the diaphragm.

10. In an electro-magnetic sound reproducer the combination, a support, an armature,

a means for creating v'ariable magnetic lines of force to actuate the armature, of sets of flexible portions arranged parallel to each other and connected with the support and wholly carrying the armature so that when it vibrates it will move strictly in the direction of the magnetic lines of force, a stylus upon the armature, a diaphragm actuated by the stylus.

11. In an .electro-magnetic sound reproducer the combination, a support, a perma nent magnet carried by said support, of lugs secured to the ends of the magnet, p'ole pieces secured to the lugs extending towards each other and overlapping to form a pair of air gaps spaced from each other, an armature having its ends extending into the spaced air gaps, means for creating variable magnetic lines of force at the poles to CHALSG the armature to move between the same, a stylus rigidly connected through the center of the arma-' ture and extending in the direction of the lines of force, spaced bars arranged in parallel to each other and the armature and. arranged cross-Wise thereto and having their ends secured to the support and having their center portions connected to the stylus so that the same and the armature are Wholly carried thereby, flexible portions formed in said spaced bars at equal distances from the stylus to permit the armature to vibrate and to guide the stylus in a strictly longitudinal movement in a direction of the lines of force,

a diaphragm actuated by the stylus. V,

12. In an electro-magnetic sound reproducer the combination, a support, a pennanent magnet carriedthereby, lugs secured to the ends of the magnet, pole pieces on saidlugs extending towards each other and over lapping to form apair of air gaps spaced from one,another, an armature having its ends positioned in the air gaps, means upon the suppgrtrto movably support the anmature in said air gaps, coils having holes to which the armature extends mounted upon each side of the center of the armature and having. the edges of the holes facing the center of the armature beveled, means for energizing the coils, means upon the-armature to actuate a diaphragm.

13. In an electro-magnetic. sound reproducer the combination, a support, a means for creating variable magnetic lines of force, an

armature arranged transversely to said lines and adapted to be actuated thereby, a stylus centrally connected to the armature and extending in the direction of the lines of force, spaced bars arranged in parallel to each other and the armature and having their ends adjustably secured to the support and having their center portions adjustably connected to the stylus, of flexible portions in said bars.to permit the stylus to move strictly longitudinally in the direction of the lines of force when the armature is actuated, a diaphragm actuated by the stylus.

' ranged in parallel into each other and the 14. In an electromagnetic sound reproducer the combination, a support, a" permanent magnet carried by said support, of

lugs secured to the ends of the magnet,

pole pieces secured to the lugs extending a-rmature and arranged crosswise thereto and having their ends secured to the support and having their center portions connected to the stylus so that the same and thearmature are wholly carried thereby, flexible portions formed in said spaced bars at equal distances from. the stylus to permit the armature to vibrate and to guide'the stylus in a strictly longitudinal movement 'in the direction of the lines'of force and to -normallyretnrn the armature to its central position, a diaphragm actuated by the stylus.

15. In an electromagnetic sound reproducer the combination, a support, a permanent magnet carried thereby, lugs secured to the ends of the magnet, pole pieces on said lugs extending towards each other and overlapping to form a-pair of air gaps spaced. from one another, an armature centrally positioned in said air gaps, means for creating variable lines of force to cause the armature to vibrate to and from the poles across its central position, means upon the support to wholly carry and to yieldingly hold the armature in a central position in the air gaps against the forces of the magnetic poles and to guide the armature strictlyin the direction of the magnetic I varia-ble'lines of force when actuated thereby, means upon the armature to actuate a diaphragm and wholly support the sam New York May 15, 1926.

' GUS NEMNICH. 

